This invention relates to a light source mounting apparatus for use in liquid crystal projector.
Liquid crystal projector is an image displaying technique well known in the art. Its general operation principle is illustrated in FIG. 1. A light generator 10 has a lamp located in a reflector 11 (which contains a parabolic reflection mirror) to generate reflecting parallel light rays passing through a illumination system 80, a liquid crystal display panel 40 and a recombination system 90, and a lens 50 to project the original image from the liquid crystal display panel 40 to a front screen 60.
When there is a need to replace the lamp, the light generator 10 must be taken out or restored through a light source mounting apparatus (referring to FIGS. 2 and 3). For instance, the liquid crystal projector made by Epson Co. of Japan has a light source mounting apparatus which includes a steel wire 71 engaged with the outer side of the light generator 10 to couple the light generator 10 with a lamp frame 70. Then the lamp frame 70 and light generator 10 are mounted in a casing 30 to complete the assembly. For disassembly, the first step is to move a handle 231 to disengage the assembly of the lamp frame 70 and light generator 10 from the casing 30. Such a design has problems in use, notably:
1. When to mount the light generator 10 on the lamp frame 70, it takes a great force from the user to engage the steel wire 71 with the light generator 10. Of course, when to replace the light generator 10, the steel wire 71 also has to be removed. It gives user similar difficulty.
2. When to reassemble, such a structure is not able to guide the light generator 10 accurately returning to its original optical path before the disassembly.
As every assembly step will create a tolerance, the accumulated tolerance tends to produce a large deviation from the original optical path and will result in project color shift, non-uniformity and decreasing of light intensity.
3. When to replace the lamp, the handle 231 has to be pulled with a great force to remove the assembly of the lamp frame 70 and light generator 10 from the casing 30. Due to the tightly engagement of the power supply plug, the pulling of the handle 231 could easily deform the handle 231 and makes it detached from the lamp frame 70. From operation perspective, when the handle 231 is not use, it relies the deforming elastic force of the handle 231 to dispose it flatly at the bottom of the lamp frame, therefore will result in a complicated shape and takes more space. It is obviously that there are still rooms for improvement.
The primary object of this invention is to provide a light source mounting apparatus for liquid crystal projector that enables the light generator automatically positioning precisely when it is disassembled and reassembled again to ensure the projecting light returning to its original designed optical path.
The light source mounting apparatus according to this invention comprises a lamp base and a casing. The lamp base is a board including a holding unit. The casing provides a space for housing at least the lamp base, a front positioning plane and a strip spring located at the front positioning plane. When the whole structure has been disassembled and reassembled again, the holding unit forces the light generator located thereon automatically pressing against the front positioning plane for rapidly finishing the initial positioning, and the strip spring has a rear end to engage with the light generator tightly when the two elements are coupled together such that the light generator will press against the front positioning plane tightly to automatically finish positioning thereby to return the optical path in coincidence with the one prior to the disassembly.
The foregoing and additional objects, features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.